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/*
* Copyright (C) 2009-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "JSExportMacros.h"
#include <cstddef>
#include <wtf/Atomics.h>
#include <wtf/HashTraits.h>
#include <wtf/Noncopyable.h>
#include <wtf/VectorTraits.h>
namespace JSC {
class WeakImpl;
class WeakHandleOwner;
class VM;
template<typename T> class Weak {
WTF_MAKE_NONCOPYABLE(Weak);
public:
Weak() = default;
constexpr Weak(std::nullptr_t)
: Weak()
{
}
Weak(T*, WeakHandleOwner* = nullptr, void* context = nullptr);
Weak(VM&, T* t, WeakHandleOwner* owner = nullptr, void* context = nullptr)
: Weak(t, owner, context)
{
}
bool isHashTableDeletedValue() const;
Weak(WTF::HashTableDeletedValueType);
constexpr bool isHashTableEmptyValue() const { return !impl(); }
Weak(Weak&&);
~Weak()
{
clear();
}
inline void swap(Weak&);
inline Weak& operator=(Weak&&);
inline bool operator!() const;
inline T* operator->() const;
inline T& operator*() const;
inline T* get() const;
inline void set(VM&, T*);
inline bool was(T*) const;
inline explicit operator bool() const;
inline WeakImpl* leakImpl() WARN_UNUSED_RETURN;
WeakImpl* unsafeImpl() const { return impl(); }
void clear();
private:
static inline WeakImpl* hashTableDeletedValue();
WeakImpl* impl() const { return m_impl; }
WeakImpl* m_impl { nullptr };
};
} // namespace JSC
namespace WTF {
template<typename T> struct VectorTraits<JSC::Weak<T>> : SimpleClassVectorTraits {
static constexpr bool canCompareWithMemcmp = false;
};
template<typename T> struct HashTraits<JSC::Weak<T>> : SimpleClassHashTraits<JSC::Weak<T>> {
typedef JSC::Weak<T> StorageType;
typedef std::nullptr_t EmptyValueType;
static EmptyValueType emptyValue() { return nullptr; }
static constexpr bool hasIsEmptyValueFunction = true;
static bool isEmptyValue(const JSC::Weak<T>& value) { return value.isHashTableEmptyValue(); }
typedef T* PeekType;
static PeekType peek(const StorageType& value) { return value.get(); }
static PeekType peek(EmptyValueType) { return PeekType(); }
};
} // namespace WTF
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